1. Field of the Invention
This invention relates in general to fertilizer and chemical-spreading systems for use with farm vehicles.
2. Description of the Prior Art
Fluid sprayer systems which attach to farm vehicles are well known to the agricultural industry. The typical construction is to attach a pair of spray booms to the rear of a farm vehicle, connect chemical tank hoses to spray nozzles on each boom, and dispense fluid fertilizer and chemicals from the chemical tank through the spray nozzles to crops and farmland. The booms are attached to the farm vehicle so that when in use, the booms extend in a horizontal position a few feet above the ground in a vertical plane which is perpendicular to the direction of travel of the truck.
The patents of Loeffler, U.S. Pat. No. 3,580,505 and Hall, U.S. Pat. No. 3,972,476 disclose spray boom assemblies of the type described. One consideration with such devices is what to do with the booms when they are not horizontally extended and in use. The patents of Holloway, U.S. Pat. No. 3,587,624 and Robinson et al., U.S. Pat. No. 3,927,832 disclose one means of storage for spray booms when they are not in use. In Holloway and Robinson, the booms are hinged to a supporting structure which is attached to a truck. The devices disclosed in these two patents include means to draw the booms inwardly to a position adjacent to the sides of the truck. One disadvantage with this mode of not-in-use storage is that the side windows of the cab of the truck are blocked, thereby preventing ingress to or egress from the cab. Another disadvantage is that when the spraying system is turned off, some of the chemical remains in the hose lines. Thus when the booms are positioned adjacent to the sides of the truck, this chemical which remains will drain out of the spraying nozzles onto the truck. Since most of the agricultural chemicals used are caustic, this drainage will result in corrosion to the metal of the truck.
The drawbacks of having the side windows blocked by the booms when in a closed position and the drainage of chemicals onto the truck are resolved by the devices disclosed by the patents of Widmer, U.S. Pat. No. 3,887,132 and Jackson, U.S. Pat. No. 3,902,667 which include means to individually raise each boom to an elevated position above the cab side windows. This elevating, as well as the closing of the booms inwardly towards the side of the truck, is performed by means of hydraulic cylinders in cooperation with mechanical linkages.
One further disadvantage of all of the prior art which has been referenced is that the mechanisms to accomplish the closing and elevating are complex and involve intricate linkages and mechanical connections. Consequently, when the vehicle is driven with the spray booms extended, shock and vibration will be encountered and subject the spraying system to mechanical failures resulting in downtime.